CN103339810A - Spark plug - Google Patents
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- CN103339810A CN103339810A CN2012800075948A CN201280007594A CN103339810A CN 103339810 A CN103339810 A CN 103339810A CN 2012800075948 A CN2012800075948 A CN 2012800075948A CN 201280007594 A CN201280007594 A CN 201280007594A CN 103339810 A CN103339810 A CN 103339810A
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- central electrode
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/02—Details
- H01T13/04—Means providing electrical connection to sparking plugs
- H01T13/05—Means providing electrical connection to sparking plugs combined with interference suppressing or shielding means
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/34—Sparking plugs characterised by features of the electrodes or insulation characterised by the mounting of electrodes in insulation, e.g. by embedding
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- Spark Plugs (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
Abstract
This invention addresses the problem of providing a spark plug having excellent adhesion between the central electrode and a sealing material. This spark plug is characterized in that it has: an insulating body, having a shaft hole extending in the axial direction, a first inner circumferential surface extending to the tip-side of the aforementioned shaft hole, a second inner circumferential surface extending to the rear end-side of the aforementioned shaft hole and having a larger inner diameter than that of the first inner circumferential surface, and a ledge part connecting the first inner circumferential surface and the second inner circumferential surface; a central electrode, having a head part supported by the ledge part and extending in the space enclosed by the second inner circumferential surface, and a columnar leg part connected to the tip of the aforementioned head part and extending in the space enclosed by the first inner circumferential surface; and a sealing material that holds the central electrode in the shaft hole. This spark plug also is characterized in that, when the position where the average outer diameter of the leg part of the central electrode begins to increase from the leg part toward the rear end is taken as the position P1, the axial distance from the position P1 to the tip of the central electrode is 15 mm or greater, and the axial distance from the position P1 to the rear end of the central electrode is 3.8 mm or greater.
Description
Technical field
The present invention relates to a kind of spark plug of the igniting for internal combustion engine, particularly make central electrode be fixed in spark plug in the axis hole of insulator well.
Background technology
The spark plug that is used for the igniting usefulness of internal combustion engines such as motor car engine generally includes: the cylindrical main body accessory; Be configured in the insulator of the tubular in the endoporus of this main body accessory; Be configured in the central electrode in the front axis hole of this insulator; Be configured in the terminal fittings in the other end side shaft hole; Relative with central electrode with the front joint of an end and main body accessory and the other end and form the grounding electrode of spark-discharge gap.
But in recent years, developed following technology: the raising of the output that realizes by booster prolongs operating range with less fuel.In such internal combustion engine, combustion chamber temperature has the trend of rising, and it is more harsh that the environment for use of spark plug becomes.If spark plug carries out the rising of temperature and decline (below be sometimes referred to as the cold and hot cycle) repeatedly in the combustion chamber, then central electrode is lax or rock in the axis hole of insulator sometimes.That is, when central electrode is fixed in the axis hole of insulator by seal member, owing to carry out the cold and hot cycle repeatedly, the bed knife of central electrode and seal member is reduced.
For such problem, for example, in order to improve the constant intensity of central electrode in insulator, in the claim 1 of patent documentation 1, be described below: " a kind of spark plug is characterized in that, is formed with groove in the periphery of the head of above-mentioned central electrode ".
And, in order to guarantee full intensity, resistance to impact by the glass capsulation parts, in the claim 1 of patent documentation 2, be described below: " a kind of spark plug; it is characterized in that; the diameter d 2 of the inner diameter d 0 in the hole, above-mentioned big footpath of above-mentioned axis hole, the diameter d 1 of above-mentioned flange shape portion, above-mentioned head is in the scope of 0≤d1-d2≤1mm, and the flange head length h from the outer rim of the front of above-mentioned flange shape portion to the rear end of above-mentioned head is at 2.0≤h≤3.0mm and in the scope (d0-d1) * 5 ± 25% ".
The prior art document
Patent documentation
Patent documentation 1: TOHKEMY 2010-267425 communique
Patent documentation 2: No. 3497009 communique of Japan Patent
Summary of the invention
The problem that invention will solve
Problem of the present invention is to provide the good spark plug of adaptation of a kind of central electrode and seal member.
Be used for solving the means of problem
The means that are used for the above-mentioned problem of solution are as follows:
(1) a kind of spark plug comprises:
Insulator, extends and has second inner peripheral surface of the internal diameter bigger than described first inner peripheral surface and a frame portion that connects described first inner peripheral surface and described second inner peripheral surface to the rear end side of described axis hole first inner peripheral surface that comprises the axis hole that extends along axis direction, extends to the front of described axis hole;
Central electrode comprises being supported in described portion and extending to the head in the space that is surrounded by described second inner peripheral surface and arrange and extend to columned foot the space that is surrounded by described first inner peripheral surface continuously from the front end of described head; With
Seal member remains in the described axis hole described central electrode by being filled in the space that is surrounded by described portion, described second inner peripheral surface and described head,
Described spark plug is characterised in that,
If will be in described central electrode from described foot towards the rear end and be made as position P1 with position that the mean outside diameter H phase diameter group of described foot begins to enlarge, be 15mm when above at the axis direction from described position P1 to the front end of described central electrode apart from E then, the axis direction distance A from described position P1 to the rear end of described central electrode is more than the 3.8mm.
As the optimal way of the spark plug of above-mentioned (1), for example as following mode.
(2) above-mentioned mean outside diameter H is more than the 1.7mm.
(3) in above-mentioned (1) or (2) related spark plug, described head comprise along the outstanding large-diameter portion of diametric(al) and from the rear end of described large-diameter portion side-prominent protuberance to the back-end,
When supposition had the cylinder S1 of the minimum diameter that can surround described protuberance, the internal diameter B of described cylinder S1 was littler than the external diameter of described large-diameter portion, and was below the above 3.3mm of 2mm.
(4) in arbitrary spark plug of above-mentioned (1)～(3), in described central electrode, if the border of described large-diameter portion and described protuberance is made as position P2, then the axis direction distance C between described position P2 and the described position P1 is below the above 3mm of 0.5mm.
(5) in arbitrary spark plug of above-mentioned (1)～(4), above-mentioned axis direction distance A is more than the 4mm.
(6) in arbitrary spark plug of above-mentioned (1)～(5), be 3.5mm at the internal diameter F of the above-mentioned insulator of the rear end of above-mentioned central electrode.
(7) in arbitrary spark plug of above-mentioned (1)～(6), above-mentioned axis direction distance A is more than the 4.5mm.
(8) in arbitrary spark plug of above-mentioned (1)～(7), be below the 2.9mm at the internal diameter F of the above-mentioned insulator of the rear end of above-mentioned central electrode.
The invention effect
Be 15mm when above at above-mentioned axis direction apart from E, the above-mentioned axis direction distance A of spark plug of the present invention is more than the 3.8mm, is preferably more than the 4.5mm, and therefore the good spark plug of adaptation of central electrode and seal member can be provided.
The internal diameter B of the above-mentioned cylinder S1 of spark plug of the present invention is littler and be below the above 3.3mm of 2mm than the external diameter of above-mentioned large-diameter portion, and/or above-mentioned axis direction distance C is below the above 3mm of 0.5mm, and therefore the better spark plug of adaptation of central electrode and seal member enough is provided.
Be more than the 1.7mm and/or the internal diameter F of above-mentioned insulator is below the 3.5mm, when particularly 2.9mm is following at above-mentioned mean outside diameter H, spark plug of the present invention effect for the raising of the adaptation of central electrode and seal member is good especially.
Description of drawings
Fig. 1 analyses and observe key diagram as the integral body of the spark plug of an embodiment of spark plug involved in the present invention.
Fig. 2 analyses and observe key diagram as the major part of the spark plug of an embodiment of spark plug involved in the present invention.
Fig. 3 (a)～(c) analyses and observe key diagram as the major part of the central electrode of an embodiment of the central electrode of spark plug involved in the present invention.
Embodiment
Fig. 1 represents the spark plug as an embodiment of spark plug involved in the present invention.Fig. 1 analyses and observe key diagram as the integral body of the spark plug 1 of an embodiment of spark plug involved in the present invention.In addition, the axis with insulator be made as O, in Fig. 1 be made as below the paper axes O preceding extreme direction, will be made as the back extreme direction of axes O above the paper and describe.
This spark plug 1 comprises: insulator 3 has the axis hole 2 that extends along the axes O direction; Central electrode 4 remains on the front of above-mentioned axis hole 2 by seal member 6; Terminal fittings 5 remains on the rear end side of above-mentioned axis hole 2; Main body accessory 7 holds above-mentioned insulator 3; Grounding electrode 8, the front end face that is configured to an end and aforementioned body accessory 7 engage and the other end relative with above-mentioned central electrode 4 via the gap.
The shape of above-mentioned grounding electrode 8 and structure for example are designed to have roughly prism-shaped, and an end engages with the front end face of main body accessory 7, bends to roughly L word on the way, and its leading section is relative with the leading section of central electrode 4 via the gap.Grounding electrode 8 is by forming with the material identical materials that forms central electrode 4.
Above-mentioned terminal fittings 5 is for being applied to the terminal of central electrode 4 for the voltage that carries out sparkover between central electrode 4 and grounding electrode 8 from the outside.Terminal fittings 5 comprises: flange part 10, its external diameter are bigger and expose from axis hole 2 than the internal diameter of axis hole 2, and its part is connected to the rear end side end face of the axes O direction of insulator 3; Roughly columned bar-shaped 11, extend and be contained in the axis hole 2 from the front end face forward end direction of the axes O direction of flange part 10.Terminal fittings 5 is formed by for example mild steel etc., forms the Ni metal level on its surface by electroplating to wait.
Above-mentioned insulator 3 is remained in the interior perimembranous of main body accessory 7 via talcum (talc) 12 or filler 13 etc.Insulator 3 comprises: first inner peripheral surface 14, extend to the front of above-mentioned axis hole 2; Second inner peripheral surface 15 extends and has than the bigger internal diameter of above-mentioned first inner peripheral surface 14 to the rear end side of above-mentioned axis hole 2; With frame portion 16, connect above-mentioned first inner peripheral surface 14 and above-mentioned second inner peripheral surface 15.Insulator 3 is fixed in main body accessory 7 under the state outstanding from the front end face of main body accessory 7 of the end of its preceding extreme direction.Preferred insulator 3 is the materials with mechanical strength, calorific intensity, electrical strength etc., as such material, for example as the ceramic sintered bodies based on aluminium oxide.
Above-mentioned central electrode 4 comprises: head 17 is supported in above-mentioned portion 16 and extends in the space that is surrounded by above-mentioned second inner peripheral surface 15; Columned foot 18 arranges and extends to the space that is surrounded by above-mentioned first inner peripheral surface 14 from the front end of above-mentioned head 17 is continuous; With leading section 29, arrange and compare reduced with the external diameter of foot and also extend from the front end of foot 18 is continuous, the front end of above-mentioned central electrode 4 insulate under the state outstanding from the front end face of insulator 3 and remains in main body accessory 7.Above-mentioned head 17 comprise along the outstanding large-diameter portion 19 of diametric(al) and from the rear end of above-mentioned large-diameter portion 19 side-prominent protuberance 20 to the back-end.Above-mentioned leading section 29 exposes from the front end face of insulator 3 and has truncated cone.In this mode, above-mentioned leading section 29 integral body are exposed from the front end face of insulator 3, still also can be that the part of above-mentioned leading section 29 extends in the space that is surrounded by first inner peripheral surface 14.Central electrode 4 is preferably formed by the material with heat conductivity and mechanical strength etc., for example, is formed by alloy such as base such as Ying Kenaier (Inconel, trade (brand) name) 600 Ni such as grade.Central electrode 4 also can have axle center part 28, it is enclosed in inside by the skin 27 that is formed by Ni base alloy etc., this axle center part 28 forms by comparing the higher material of pyroconductivity with above-mentioned outer 27, and can give an example as Cu, Cu alloy, Ag or Ag alloy etc. as the material that forms above-mentioned axle center part 28.
Above-mentioned seal member 6 remains on above-mentioned central electrode 4 in the above-mentioned axis hole 2 by being filled in the space that is surrounded by above-mentioned portion 16, above-mentioned second inner peripheral surface 15 and above-mentioned head 17.Can the sealing powder that comprise metal dusts such as glass powder, Cu, Fe such as sodium borosilicate glass be carried out sintering and form seal member 6.The resistance value of seal member 6 is generally below hundreds of m Ω.
Between central electrode 4 and terminal fittings 5, resistive element 21 is set via above-mentioned seal member 6.Resistive element 21 is electrically connected central electrode 4 and terminal fittings 5, prevents the electric wave generating noise by this resistive element 21.Can be to containing glass powder, ZrO such as sodium borosilicate glass
2Resistive element constituent Deng metal dusts such as nonmetal electroconductive powder such as ceramic powders, carbon black and/or Zn, Sb, Sn, Ag, Ni etc. carries out sintering and forms resistive element 21.The resistance value of this resistive element 21 is generally more than 100 Ω.
In such mode, between resistive element 21 and terminal fittings 5, be provided with by second seal member 22 that forms with above-mentioned seal member 6 identical materials, insulator 3 also is fixed in terminal fittings 5 sealings.Second seal member 22 is set as required, under the situation that does not have second seal member 22, by above-mentioned resistive element 21 with terminal fittings 5 sealing and be fixed in insulator 3.
As shown in Figure 2, if this spark plug will be in central electrode 4 from foot 18 towards the rear end and be made as position P1 with position that the mean outside diameter H phase diameter group of foot 18 begins to enlarge, be that 15mm is when above at the axis direction from above-mentioned position P1 to the front end of above-mentioned central electrode 4 apart from E then, axis direction distance A from above-mentioned position P1 to the rear end of above-mentioned central electrode 4 is more than the 3.8mm, be preferably more than the 4mm, more preferably more than the 4.5mm.
If spark plug carries out rising and the decline of temperature repeatedly in the combustion chamber, then carry out the following cycle repeatedly: the heat that the sparkover that produces between central electrode 4 and grounding electrode produces and the heat in the combustion chamber etc. are transmitted to from the front end of central electrode 4 head 17 of distolateral configuration backward, the temperature of the head 17 of central electrode 4 rises, and placement is after this cooled off and temperature is descended.If carry out so cold and hot cycle repeatedly, then owing to form the difference of material with the material coefficient of thermal expansion coefficient that forms seal member 6 of central electrode 4, near the seal member 6 the boundary face of head 17 and seal member 6 forms a plurality of pores.Spark plug carries out the cold and hot cycle repeatedly and its temperature difference is more big, and then the thermal expansion of head 17 becomes more big and more easy formation pore.And, between pore and pore, be easy to generate the crack.And then, if make internal combustion engine operation then produce vibration, therefore between formed pore and pore, be easy to generate the crack, and then the space increases easily.
But, if above-mentioned axis direction distance A is in above-mentioned scope, then by reducing the thermal expansion of head 17, be suppressed at form pore on the seal member 6 and be suppressed at pore and pore between form the crack, therefore the good spark plug of adaptation of central electrode 4 and seal member 6 can be provided.Even such spark plug carries out the rising of temperature and decline repeatedly and then is arranged in the harsh combustion chamber of its temperature difference, prevent that also central electrode 4 is lax or rock in the axis hole 2 of insulator 3.
Under the above-mentioned axis direction situation different apart from E, even the temperature of the leading section of central electrode 4 is identical, owing to the difference that is transmitted to the heat of head 17 from leading section, the temperature of head 17 is also inequality.Apart from E more in short-term, namely under the situation less than 15mm, the temperature of head 17 can't be suppressed at below the uniform temperature at axis direction, even therefore increase the axis direction distance A, can not obtain above-mentioned effect.On the other hand, when axis direction is longer apart from E, under the situation more than the 15mm, be more than the 3.8mm by making the axis direction distance A namely, be preferably more than the 4mm, more preferably more than the 4.5mm, thereby obtain above-mentioned effect.
In addition, be provided with under the situation of the noble metal termination 30 that is formed by noble metal at the front end of central electrode 4, with the front end of this noble metal termination 30 front end as central electrode 4.Therefore, under the situation that is provided with noble metal termination 30, above-mentioned axis direction is axis direction distance from above-mentioned position P1 to the front end of noble metal termination 30 apart from E.
Under above-mentioned axis direction distance A was situation below the 3.8mm, the temperature of head 17 became and rises easily, so the thermal expansion of head 17 becomes big, was easy to generate pore and crack in seal member 6.Therefore, the adaptation of central electrode 4 and seal member 6 is not good.If the axis direction distance A is long, for example surpass 5mm, then separate from the position that produces sparkover the position of resistive element 21, therefore exists to suppress the possibility that the electric wave anti noise reduces.Therefore, preferred axial direction distance A is below the 5mm.
The mean outside diameter H of above-mentioned foot 18 for example can measure as follows.At first, will the position of direction 1mm measure the diameter in the foot 18 of two directions of the quadrature of this mensuration starting point as measuring starting point to the back-end from the front end edge axes O of foot 18.Similarly, to measuring every the diameter of two directions of five points of 1mm along the back extreme direction from this mensuration starting point, the arithmetic mean of the measured value by calculating these 10 points can access mean outside diameter H.
Above-mentioned position P1 for from above-mentioned foot 18 towards position that back extreme direction and mean outside diameter H phase diameter group begin to enlarge, in other words, above-mentioned position P1 is, the boundary vicinity of foot 18 and large-diameter portion 19, have a front position of the axes O direction at the position of bigger external diameter always than above-mentioned mean outside diameter H.
Be 1.7mm when above at above-mentioned mean outside diameter H, the axis direction distance A is that the above effect that produces of 3.8mm is good especially.If mean outside diameter H is more than the 1.7mm, namely foot 18 is more thick, and the heat conduction velocity from the front end of foot 18 to axes O direction rear end side becomes more fast, thereby can promptly reduce the temperature of front end of the foot 18 of rising, therefore preferred the use.On the other hand, be 1.7mm when above at mean outside diameter H, the temperature of head 17 becomes and rises easily.Therefore, above-mentioned axis direction distance A is above produce above-mentioned effective of 3.8mm.And the external diameter of foot 18 gets final product for the external diameter that can be arranged in the axis hole 2, and mean outside diameter H is generally below the 5mm.
As shown in Figure 2, above-mentioned large-diameter portion 19 has wide diameter portion 23, maximum gauge portion 24 and reducing diameter part 25 in order from the front of axes O direction, is provided with protuberance 20 continuously in the rear end side of reducing diameter part 25.Above-mentioned wide diameter portion 23 is supported in above-mentioned portion 16, thereby central electrode 4 is fixed in the axis hole 2.In the present embodiment, wide diameter portion 23 forms coniform, the outer peripheral face of maximum gauge portion 24 forms cylindric, reducing diameter part 25 with columned maximum gauge portion 24 with compare the littler columned protuberance 20 of external diameter with this maximum gauge portion 24 and be connected and form and the axes O plane orthogonal.
In such execution mode, above-mentioned protuberance 20 forms cylindric, is formed with the recess 26 of inverted cone-shaped in the end with large-diameter portion 19 opposite sides of above-mentioned protuberance 20.If form recess 26, then seal member 6 and head 17 increase contacts area, so the easy driving fit that becomes of seal member 6 and head 17.
The shape of above-mentioned head 17 is not particularly limited in making central electrode 4 be supported in frame portion 16 and is fixed in the axis hole 2, for example, as shown in Figure 3, can adopt different shape.For example, shown in Fig. 3 (a), outline line for head 17a, when the front of central electrode 4a describes the shape of the head 17a the cutting plane that central electrode 4a is dissectd along axes O in order, wide diameter portion 23a constitutes the curve that projects upwards continuously from the rear end of the 18a of foot that constitutes the line segment parallel with axes O, the 24a of maximum gauge portion constitutes from the rear end of this curve continuously and the line segment parallel with axes O, reducing diameter part 25a constitutes from the rear end of this line segment outstanding curve continuously and downwards, and protuberance 20a constitutes from the rear end of this curve continuously and the line segment parallel with axes O.Outline line about the head 17b shown in Fig. 3 (b), large-diameter portion 19b constitute from the rear end of the 18b of foot that constitutes the line segment parallel with axes O continuously and to the outstanding curve of the direction of axes O quadrature, protuberance 20b constitutes continuous and with the axes O parallel line segment same with Fig. 3 (a) from the rear end of this curve.Outline line about the head 17c shown in Fig. 3 (c), wide diameter portion 23c constitutes from the rear end of the 18c of foot that constitutes the line segment parallel with axes O and the line segment of this line segment quadrature, the 24c of maximum gauge portion constitutes the line segment parallel with the axes O direction with this line segment quadrature, reducing diameter part 25c constitutes from the rear end of this line segment continuously and has the line segment of inclination with respect to axes O, protuberance 20c constitute describe from the rear end of this line segment continuously and with the line segment of the wave of axes O almost parallel.The outline line of protuberance 20c is described wave, is to realize by implement processing such as screw cutting processing on the surface of protuberance 20c.Also can with the surface that is implemented processing of the protuberance 20c of Fig. 3 (c) similarly, on the surface of the 24a～24c of maximum gauge portion, reducing diameter part 25a～25c, protuberance 20a～20c, form concavo-convex by implementing screw cutting processing and annular knurl processing etc.
When supposing the cylinder S1 that to have the minimum diameter that can surround above-mentioned protuberance 20, the internal diameter B of preferred above-mentioned cylinder S1 is littler than the external diameter of above-mentioned large-diameter portion 19, below the above 3.3mm of 2mm.The volume of the more thick then thermal expansion of protuberance 20 more increases, but the more thick then more easy heat of emitting of protuberance 20.Therefore, the internal diameter B of above-mentioned cylinder S1 is conducive to reduce the thermal expansion of protuberance 20 in above-mentioned scope.Therefore, if the internal diameter B of above-mentioned cylinder S1 in above-mentioned scope, then can provide the better spark plug 1 of adaptation of central electrode 4 and seal member 6.
In above-mentioned central electrode 4, if the border of large-diameter portion 19 and protuberance 20 is made as position P2, then preferred axis direction distance C between above-mentioned position P2 and above-mentioned position P1 is large-diameter portion 19 the axis direction distance C is below the above 3mm of 0.5mm.The volume of comparing the more long then thermal expansion of axis direction distance C of the bigger large-diameter portion of external diameter 19 with foot 18 and protuberance 20 more increases, on the other hand the more long then more easy heat of emitting of axes O direction distance C.Therefore, above-mentioned axis direction distance C is conducive to reduce the thermal expansion of large-diameter portion 19 in above-mentioned scope.If above-mentioned axis direction distance C in above-mentioned scope, then can provide the better spark plug of adaptation of central electrode 4 and seal member 6.
The axis direction distance C is the axis direction distance of position P1 and position P2, the position of position P1 be defined as above-mentioned like that, according to the shape of central electrode 4 assigned position P2 as follows.Position P2 is the border of large-diameter portion 19 and protuberance 20, and in other words, position P2 is position boundary vicinity, that external diameter changes at large-diameter portion 19 and protuberance 20.Shown in Fig. 2 and Fig. 3 (b), (c), under the clear and definite situation of the variation of external diameter, will be made as position P2 in the position of variation maximum boundary vicinity, external diameter of large-diameter portion 19 and protuberance 20.On the other hand, shown in Fig. 3 (a), boundary vicinity at large-diameter portion 19 and protuberance 20, under the indefinite situation of the variation of external diameter, to be made as position P2 as upper/lower positions: at the boundary vicinity of large-diameter portion 19 and protuberance 20, compare external diameter with the internal diameter B of the cylinder S1 of supposition as described above and begin the position that becomes big towards the preceding extreme direction of axes O.
Internal diameter F at the above-mentioned insulator 3 of the rear end of above-mentioned central electrode 4 is below the 3.5mm, when particularly 2.9mm is following, and above-mentioned axis direction A is that the above effect that produces of 3.8mm is good especially.De Zhuan Condition is in recent years, seeks the exploitation of the spark plug of miniaturization for the miniaturization of engine design and engine self freely etc., and therefore preferred above-mentioned internal diameter F is below the 3.5mm, particularly below the 2.9mm.On the other hand, if above-mentioned internal diameter F is below the 3.5mm, particularly below the 2.9mm, then as described later, the sealing powder that forms seal member 6 is filled in the axis hole 2, by heating and pressurization and with central electrode 4 sealing and when being fixed in the axis hole 2, be difficult to compression seal parts 6, therefore be easy to generate pore at seal member 6.Therefore, above-mentioned axis direction distance A is above produce effective of 3.8mm.
For example make above-mentioned spark plug 1 in such a way.
At first, by known method, make central electrode 4, grounding electrode 8, main body accessory 7, terminal fittings 5 and insulator 3 with predetermined shape, and by laser welding etc. with an engaged at end of grounding electrode 8 in the front end face of main body accessory 7.
On the other hand, central electrode 4 is inserted in the axis hole 2 of insulator 3, wide diameter portion 23 fastenings of central electrode 4 in the frame portion 16 of axis hole 2, are configured in foot 18 in the space that is surrounded by first inner peripheral surface 15, head 17 is configured in the space that is surrounded by second inner peripheral surface.。
Then, with form the sealing powder of seal member 6, the sealing powder that forms the resistive element constituent of resistive element 21 and form second seal member 22 is put into from the rear end side in the above-mentioned axis hole 2 with this order, press-on pins is inserted in the axis hole 2 and with 60N/mm
2Above pressure carries out precommpression.
Then, with bar-shaped 11 of the rear end side insertion end subassembly 5 in above-mentioned axis hole 2 and make bar-shaped 11 and seal the mode that powder contacts and dispose terminal fittings 5.
Then, in the temperature more than the glass softening point of the glass powder that comprises of sealing powder for example under 800～1000 ℃ the temperature, to seal powder and resistive element constituent heating 3～30 minutes, and till the front end face of the flange part 10 of terminal fittings 5 is pressed into rear end face butt with insulator 3, thereby compression and heated sealant powder and resistive element constituent.
Like this sealing powder and resistive element constituent are carried out sintering and form resistive element 21, seal member 6 and second seal member 22, make central electrode 4 and terminal fittings 5 seal and be fixed in the axis hole 2 by seal member 6 and second seal member 22.At this moment, because the difference of the thermal coefficient of expansion of central electrode 4 and seal member 6 forms a plurality of pores near the seal member 6 the boundary face of central electrode 4 and seal member 6.
Then, the insulator 3 that central electrode 4 and terminal fittings 5 etc. are fixedly arranged is assembled in the main body accessory 7 that joint has grounding electrode 8.
Last so that the leading section of grounding electrode 8 is bent and make the end mode relative with the leading section of central electrode 4 of grounding electrode 8 make spark plug 1 to central electrode 4 lateral bendings.
The internal combustion engine that spark plug involved in the present invention is used for automobile-use is the spark plug of petrol engine etc. for example, the set screwed hole of cap (not shown) of the combustion chamber of above-mentioned threaded portion and division and formation internal combustion engine is screwed, thereby is fixed on preposition.Spark plug involved in the present invention can be applied to internal combustion engine arbitrarily, but in combustion chamber up to now for bringing into play effect especially in the employed spark plug under the environment of high temperature.
Spark plug involved in the present invention is not limited to above-described embodiment, in the scope of the purpose that can realize the present application, can carry out various changes.For example, irrelevant with the diameter of thread, as long as satisfy above-mentioned necessary condition, spark plug involved in the present invention just can provide the good spark plug of adaptation of central electrode and seal member.
And, the axle center part 28 of the spark plug 1 of above-mentioned execution mode exposes at rear end face and the rear end outer peripheral face of central electrode 4, but also can be that 28 rear end faces at central electrode 4 of axle center part expose, and also can be that axle center part 28 does not expose and covers whole axle center parts 28 by outer 27.Spark plug involved in the present invention, with axle center part to expose state irrelevant, as long as satisfy above-mentioned necessary condition, spark plug involved in the present invention just can provide the good spark plug of adaptation of central electrode and seal member.
Both the noble metal termination 30,31 that can be formed by platinum alloy and iridium alloy etc. in the relative face setting of above-mentioned central electrode 4 and above-mentioned grounding electrode 8 also can an either party at above-mentioned central electrode 4 and above-mentioned grounding electrode 8 arrange the noble metal termination.In the spark plug 1 of the manner, both are provided with noble metal termination 30,31 above-mentioned central electrode 4 and above-mentioned grounding electrode 8, form spark-discharge gap g between each noble metal termination 30,31.
Embodiment
The making of＜spark plug＞
Have the spark plug identical shaped with spark plug shown in Figure 1 according to the making of above-mentioned manufacturing process.Make internal diameter (F), the rear end from position P1 to central electrode of insulator axis direction distance (A), have the axis direction distance (C) internal diameter (B), position P1 and the position P2 of the cylinder S1 that protuberance can be enclosed in inner minimum diameter, the axis direction distance (E) of the front end from position P1 to central electrode, the axis direction distance (G) of the rear end from position P2 to central electrode, the mean outside diameter (H) of foot and change, thereby make the spark plug with the various sizes shown in the table 1.
About above-mentioned various sizes, use Toshiba's little CT scan machine of system (TOSCANER) and measure (F) by stereo-picture.From spark plug, take out central electrode and measure (A), (B), (C), (E), (G), (H) by projector.As mentioned above, will from the front end edge axis of columned foot to the back-end the position of direction 1mm as measuring starting point, to from this mensuration starting point to the back-end direction measure and calculate (H) every the diameter of two directions of five points of 1mm.(B) for measuring the maximum gauge of protuberance.
In addition, except implementing screw thread processing on the surface of the protuberance of central electrode, the spark plug of the test No.12 of table 1 is identical with the shape of central electrode shown in Figure 1.Except being shaped as the shape by three-jaw chuck processing of the protuberance of central electrode, the spark plug of the test No.13 of table 1 is identical with the shape of central electrode shown in Figure 1.(B) about protuberance with these shapes, from protuberance being photographed with projector with the direction of the axis quadrature of central electrode and measure the diametric Breadth Maximum of protuberance, then, make 60 ° of central electrode rotations, measure the Breadth Maximum of protuberance, will similarly make 60 ° of central electrode rotations at every turn and maximum in six measured values of total of measuring as (B).
And central electrode has the axle center part that is formed by the metal that with Cu is principal component and the skin that is formed by the metal that with Ni is principal component, and this skin is enclosed in inside with this axle center part, is 0.4mm at the outer field thickness of position P2.
＜evaluation method＞
(resistance to impact test)
In the spark plug of making heat by burner so that the leading section of central electrode reaches 800 ℃ mode, carry out the resistance to impact test according to 7.4 of JIS B8031 after, place cooling, this as one-period, is carried out the above-mentioned cycle repeatedly.Every resistance value of measuring the resistive element of spark plug through one-period, be 0.6 when following being made as R0, the value of R1/R0 in the time of will being made as R1 with the resistance value that 3kV measures with the resistance value that 12V measures, finish test, according to the periodicity of this moment, the adaptation of assessment centers electrode and seal member.Metewand is as follows.In table 1, represent the result.
1: less than one-period
2: one-period is above less than two cycles
3～8: when above two cycles, every process one-period adds a bit
9: nine cycles are above less than ten cycles
10: ten more than the cycle
[table 1]
In the spark plug of making, except so that the leading section of central electrode reaches 850 ℃ mode heats by burner, similarly test with test No.1～40.In table 2, represent the result.
[table 2]
Shown in table 1 and table 2, even the spark plug that is included in the scope of the present invention carries out the cold and hot cycle repeatedly, the adaptation of central electrode and seal member also keeps well, and resistance value is difficult to improve.
Label declaration
1 spark plug
2 axis holes
3 insulators
4 central electrodes
5 terminal fittings
6 seal members
7 main body accessories
8 grounding electrodes
9 threaded portions
10 flange parts
11 bar-shaped portions
12 talcums
13 fillers
14 first inner peripheral surfaces
15 second inner peripheral surfaces
16 portions
17 heads
18 foots
19 large-diameter portions
20 protuberances
21 resistive elements
22 second seal members
23 wide diameter portions
24 maximum gauge portions
25 reducing diameter parts
26 recesses
27 skins
28 axle center parts
29 leading sections
30,31 noble metal terminations
Claims (8)
1. spark plug comprises:
Insulator, extends and has second inner peripheral surface of the internal diameter bigger than described first inner peripheral surface and a frame portion that connects described first inner peripheral surface and described second inner peripheral surface to the rear end side of described axis hole first inner peripheral surface that comprises the axis hole that extends along axis direction, extends to the front of described axis hole;
Central electrode comprises being supported in described portion and extending to the head in the space that is surrounded by described second inner peripheral surface and arrange and extend to columned foot the space that is surrounded by described first inner peripheral surface continuously from the front end of described head; With
Seal member remains in the described axis hole described central electrode by being filled in the space that is surrounded by described portion, described second inner peripheral surface and described head,
Described spark plug is characterised in that,
If will be in described central electrode from described foot towards the rear end and be made as position P1 with position that the mean outside diameter H phase diameter group of described foot begins to enlarge, be 15mm when above at the axis direction from described position P1 to the front end of described central electrode apart from E then, the axis direction distance A from described position P1 to the rear end of described central electrode is more than the 3.8mm.
2. spark plug according to claim 1 is characterized in that, described mean outside diameter H is more than the 1.7mm.
3. spark plug according to claim 1 and 2 is characterized in that,
Described head comprise along the outstanding large-diameter portion of diametric(al) and from the rear end of described large-diameter portion side-prominent protuberance to the back-end,
When supposition had the cylinder S1 of the minimum diameter that can surround described protuberance, the internal diameter B of described cylinder S1 was littler than the external diameter of described large-diameter portion, and was below the above 3.3mm of 2mm.
4. according to each described spark plug of claim 1-3, it is characterized in that,
In described central electrode, if the border of described large-diameter portion and described protuberance is made as position P2, then the axis direction distance C between described position P2 and the described position P1 is below the above 3mm of 0.5mm.
5. according to each described spark plug of claim 1-4, it is characterized in that,
Described axis direction distance A is more than the 4mm.
6. according to each described spark plug of claim 1-5, it is characterized in that,
Internal diameter F at the described insulator of the rear end of described central electrode is below the 3.5mm.
7. according to each described spark plug of claim 1-6, it is characterized in that,
Described axis direction distance A is more than the 4.5mm.
8. according to each described spark plug of claim 1-7, it is characterized in that,
Internal diameter F at the described insulator of the rear end of described central electrode is below the 2.9mm.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011020954 | 2011-02-02 | ||
| JP2011-020954 | 2011-02-02 | ||
| PCT/JP2012/000687 WO2012105255A1 (en) | 2011-02-02 | 2012-02-01 | Spark plug |
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| CN103339810A true CN103339810A (en) | 2013-10-02 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2012800075948A Pending CN103339810A (en) | 2011-02-02 | 2012-02-01 | Spark plug |
| CN201280007532.7A Active CN103339809B (en) | 2011-02-02 | 2012-02-02 | Spark plug |
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| CN201280007532.7A Active CN103339809B (en) | 2011-02-02 | 2012-02-02 | Spark plug |
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| US (2) | US9124073B2 (en) |
| EP (2) | EP2672587B1 (en) |
| JP (2) | JP5414896B2 (en) |
| KR (1) | KR101515314B1 (en) |
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| WO (2) | WO2012105255A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107534272A (en) * | 2015-04-28 | 2018-01-02 | 日本特殊陶业株式会社 | Spark plug |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014038773A (en) * | 2012-08-17 | 2014-02-27 | Ngk Spark Plug Co Ltd | Spark plug |
| JP5616946B2 (en) * | 2012-11-28 | 2014-10-29 | 日本特殊陶業株式会社 | Spark plug |
| JP5809673B2 (en) * | 2013-09-09 | 2015-11-11 | 日本特殊陶業株式会社 | Spark plug |
| DE102014223746A1 (en) | 2014-11-20 | 2016-05-25 | Robert Bosch Gmbh | Spark plug and method of making a spark plug |
| DE102014226226A1 (en) * | 2014-12-17 | 2016-06-23 | Robert Bosch Gmbh | A method of manufacturing a spark plug electrode having a core extending to the firing surface |
| JP6157519B2 (en) * | 2015-01-27 | 2017-07-05 | 日本特殊陶業株式会社 | Spark plug |
| JP6087991B2 (en) | 2015-06-22 | 2017-03-01 | 日本特殊陶業株式会社 | Spark plug |
| JP6087990B2 (en) | 2015-06-22 | 2017-03-01 | 日本特殊陶業株式会社 | Spark plug |
| JP6025921B1 (en) * | 2015-06-22 | 2016-11-16 | 日本特殊陶業株式会社 | Spark plug |
| US9570889B2 (en) * | 2015-07-15 | 2017-02-14 | Ngk Spark Plug Co., Ltd. | Spark plug |
| JP6490025B2 (en) * | 2016-04-25 | 2019-03-27 | 日本特殊陶業株式会社 | Spark plug |
| JP6970779B2 (en) | 2020-04-20 | 2021-11-24 | 日本特殊陶業株式会社 | Spark plug |
| JP2022045383A (en) * | 2020-09-09 | 2022-03-22 | 日本特殊陶業株式会社 | Spark plug |
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| WO2010131410A1 (en) * | 2009-05-13 | 2010-11-18 | 日本特殊陶業株式会社 | Spark plug |
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| JP3079383B2 (en) * | 1990-09-29 | 2000-08-21 | 日本特殊陶業株式会社 | Spark plug for internal combustion engine |
| JP3497009B2 (en) | 1995-05-16 | 2004-02-16 | 日本特殊陶業株式会社 | Spark plug |
| JP3500555B2 (en) | 1996-03-29 | 2004-02-23 | 日本特殊陶業株式会社 | Spark plug for internal combustion engine |
| US6191525B1 (en) * | 1997-08-27 | 2001-02-20 | Ngk Spark Plug Co., Ltd. | Spark plug |
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| JP3795374B2 (en) * | 2001-10-31 | 2006-07-12 | 日本特殊陶業株式会社 | Spark plug |
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| JP4719191B2 (en) * | 2007-07-17 | 2011-07-06 | 日本特殊陶業株式会社 | Spark plug for internal combustion engine |
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2012
- 2012-02-01 EP EP12742558.5A patent/EP2672587B1/en active Active
- 2012-02-01 JP JP2012523529A patent/JP5414896B2/en active Active
- 2012-02-01 WO PCT/JP2012/000687 patent/WO2012105255A1/en active Application Filing
- 2012-02-01 KR KR1020137022928A patent/KR101515314B1/en active IP Right Grant
- 2012-02-01 CN CN2012800075948A patent/CN103339810A/en active Pending
- 2012-02-01 US US13/983,073 patent/US9124073B2/en active Active
- 2012-02-02 EP EP12742768.0A patent/EP2672588B1/en active Active
- 2012-02-02 JP JP2012523532A patent/JP5414897B2/en active Active
- 2012-02-02 WO PCT/JP2012/000721 patent/WO2012105270A1/en active Application Filing
- 2012-02-02 CN CN201280007532.7A patent/CN103339809B/en active Active
- 2012-02-02 US US13/978,976 patent/US8963407B2/en active Active
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| JPH02165587A (en) * | 1988-12-20 | 1990-06-26 | Ngk Spark Plug Co Ltd | Central electrode for spark plug |
| JPH0844701A (en) * | 1994-08-02 | 1996-02-16 | Hirohiko Adachi | Method for predicting electron state of compound having structural defect |
| WO2010131410A1 (en) * | 2009-05-13 | 2010-11-18 | 日本特殊陶業株式会社 | Spark plug |
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| CN107534272A (en) * | 2015-04-28 | 2018-01-02 | 日本特殊陶业株式会社 | Spark plug |
| CN107534272B (en) * | 2015-04-28 | 2019-07-19 | 日本特殊陶业株式会社 | Spark plug |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2012105270A1 (en) | 2012-08-09 |
| KR20130120531A (en) | 2013-11-04 |
| WO2012105255A1 (en) | 2012-08-09 |
| JP5414897B2 (en) | 2014-02-12 |
| US20130285534A1 (en) | 2013-10-31 |
| EP2672587B1 (en) | 2019-12-25 |
| EP2672588A4 (en) | 2016-11-02 |
| US8963407B2 (en) | 2015-02-24 |
| JPWO2012105255A1 (en) | 2014-07-03 |
| US9124073B2 (en) | 2015-09-01 |
| EP2672588B1 (en) | 2017-11-29 |
| JPWO2012105270A1 (en) | 2014-07-03 |
| US20130307402A1 (en) | 2013-11-21 |
| CN103339809B (en) | 2015-07-22 |
| EP2672587A4 (en) | 2014-09-03 |
| EP2672588A1 (en) | 2013-12-11 |
| CN103339809A (en) | 2013-10-02 |
| EP2672587A1 (en) | 2013-12-11 |
| KR101515314B1 (en) | 2015-04-24 |
| JP5414896B2 (en) | 2014-02-12 |
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Application publication date: 20131002 |